长期水分亏缺对吉林省不同年代玉米品种光合及物质生产特性的影响
以吉林省20世纪70年代以来的3个不同年代大面积推广的玉米品种为材料,采用遮雨棚土柱栽培试验,研究了长期水分亏缺对不同年代玉米品种光合特性及干物质转运的影响。结果表明：与对照相比,水分亏缺使老品种(1970s和1990s)果穗叶净光合速率(Pn)、最大光化学效率(Fv/Fm)降低幅度大于当代品种(2010s),花期至花后40d,1970s、1990s和2010s玉米果穗叶Pn、Fv/Fm水分亏缺处理与对照相比各时期平均降幅分别为29.4%、21.8%、16.1%和19.4%、13.2%、11.1%。长期水分亏缺下,当代玉米品种叶片和茎鞘干物质转运率高于老品种,与对照相比,2010s、1990s和1970s玉米品种叶片和茎鞘干物质平均转运率分别提高了48.9%、47.7%和33.8%,同时水分亏缺下,玉米花前贮藏同化物转运对籽粒产量贡献率随着年代的推进而降低,而花后干物质积累量对产量贡献率则随着年代的推进而提高。可见,长期水分亏缺下,当代玉米品种花后比老品种具有更强的光化学效率,能够驱动其自身更多花前营养器官贮藏的同化物向籽粒转运,同时当代玉米品种花后干物质积累对产量贡献率较老品种更具有优势。
英文摘要:
In this paper, maize varieties which had been widely popularized since 1970s in Jilin Province released in three different eras (1970s, 1990s and contemporary era) were used as materials. The effects of long term water deficit on photosynthetic characteristics and dry matter remobilization of maize varieties in different eras were studied by tubular column cultivation experiment with rain shelter. Compared with the control, water deficit reduced the net photosynthetic rate (Pn) and maximum photochemical efficiency (Fv/Fm) of ear leaves of old varieties (1970s and 1990s) more than that of contemporary varieties (2010s). The water deficit treatments of Pn, Fv/Fm in ear leaves of maize in 1970s, 1990s and 2010 decreased by 29.4%, 21.8%, 16.1% and 19.4%, 13.2% and 11.1% respectively from flowering stage to 40 days after flowering. Under long-term water deficit, the dry matter remobilization rate of leave and stem-sheath of contemporary maize varieties was higher than that of the old ones. Relative to the control, the average translocation rate of leaf and stem-sheaths dry matter in 2010s, 1990s and 1970s increased by 48.9%, 47.7% and 33.8%, respectively. In addition, under water deficit, the contribution rate of storage assimilates before anthesis to grain yield decreased with the advancement of the era, while the contribution rate of dry matter accumulation to grain after anthesis increased with the development of the era. So, under long-term water deficit, the post-anthesis photochemistry efficiency of contemporary maize varieties is stronger than that of the old ones, which can drive more stored assimilates of vegetative organs before anthesis to transfer to grains. Meanwhile, under water deficit the contribution of post-anthesis dry matter accumulation of contemporary maize varieties to yield is more advantageous than that of the old varieties.
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